1. Field of Invention
This invention relates to a manufacturing method of the component part for a variable capacity turbine which is used in the supercharger (the exhaust gas turbocharger) of internal combustion engines or the so forth, and the structure of the component part. The variable capacity turbine is configured in such a way that the actuating gas flows from a spiral scroll formed in the turbine casing to the turbine rotor in a radial direction through multiple nozzle vanes provided with wings of a variable angle for rotating the turbine rotor. This invention relates specially to a manufacturing method of a nozzle driving member for the adjustable nozzle mechanism and a connecting member to connect the nozzle driving member and the nozzle vanes, and the structure of the component part.
2. Description of the Related Art
In order to make a good match with regard to the internal combustion engine, between the outflow exhaust gas volume from the engine and the actuating gas flow volume, which should be determined for the optimum operation condition of the supercharger, variable capacity superchargers, equipped with a variable capacity turbine capable of changing the exhaust gas volume to be sent from the spiral scroll to the turbine rotor in accordance with the operation condition of the engine, have been in widespread use in recent years.
An example of the conventional adjustable nozzle mechanism used in such variable capacity turbine is shown in FIG. 7 and FIG. 8.
FIG. 7 illustrates the essential cross sectional view (Cxe2x80x94C cross section shown in FIG. 8) highlighting the connecting portion of the link assembly and the lever plate, and FIG. 8 illustrates D-arrowed view in FIG. 7.
In FIG. 7 and FIG. 8, the link assembly 10 in the adjustable nozzle mechanism is configured by a circular shaped link plate 3 into which connecting pins 03a, which are manufactured separately from the link plate 3, are fixed in a circumferential direction by pressxe2x80x94insert or by welding, etc. In the adjustable nozzle mechanism, one end of lever plate 1 is fixed to each nozzle shaft 02 of the nozzle vane, and as shown in FIG. 7, the other end of lever plate 1 is provided with a recess 1c which engages with a connecting pin 03a of link assembly 10 with a small enough gap to maintain the normal function of the nozzle vanes (not shown in the figure).
In the prior art mentioned above, however, since the connecting pins 03a, connecting the circular-shaped link plate 3 and lever plates 1 provided in a circumferential direction, are manufactured separately from link plate 3, fixed by press-insert or by welding, etc., it is necessary to fix a number of connecting pins 03a along the circumferential direction of link plate 3 in the above mentioned way. This requires a separate process count for manufacturing the connecting pins 03a, and it also requires the assembling process to assemble the connecting pins 03a into the link plate 3. As a result, these processes drive the link assembling count and manufacturing costs higher.
An addition problem is, since link plate 3 and the connecting pins 03a are manufactured separately, the number of component parts will be increased and the total weight of link assembly 10 will also be increased. Thus the prior arts have the above mentioned problems.
In consideration of the problems with the conventional arts mentioned above, the object of this invention is to propose a manufacturing method for manufacturing a component part for the variable capacity turbine, and the structure of the nozzle driving member, which will simplify the structure of the component part for the adjustable nozzle mechanism, the manufacturing work which results in lowering the manufacturing count and cost, as well as the number of component part, and in lightening the weight of the variable capacity turbine.
The invention is applied to solve these problems, and the variable capacity turbine for applying this invention is a radial-flow variable capacity turbine. It is configured in such a way that the actuating gas is forced to flow from a spiral scroll formed in the turbine casing to the turbine rotor in a radial direction, through multiple nozzle vanes of which the angle is adjustable by the adjustable nozzle mechanism, for rotating the turbine rotor. The manufacturing method for the component part for the variable capacity turbine according to this invention is distinguished by the configuration in which, for manufacturing a connecting pin which transmits the driving force to the engaging counter member by engaging with a recess or a hole formed in the counter member out of the component parts of the adjustable nozzle mechanism, and a plate member connected to the connecting pin, the manufacturing method includes a step of forming the connecting pin as a single structure with the plate member by partially forcing a surface of the plate member to protrude in a column shape.
In this invention, when the connecting pin and the plate member are formed as a single structure, the connecting pin can be formed preferably by a pressing, in which one side surface of the plate member is pressed towards the opposite side surface by a male molder to depress and form a depressed portion, then a protrusion formed on the opposite side surface of the depressed portion is accepted into the molding cap of the female molder in order to form the connecting pin having a column shape.
As an alternative, the connecting pin can be formed preferably by precision molding as a single structure with the plate member.
Further, this invention is applied to the variable capacity turbine which is configured in the following way. The actuating gas is forced to flow from a spiral scroll formed in the turbine casing in a radial direction to the turbine rotor, through multiple nozzle vanes of which the angle is adjustable by the adjustable nozzle mechanism, for rotating the turbine rotor. The adjustable nozzle mechanism is provided on the nozzle mount fixed to the turbine casing in such a way that the mechanism is free to rotate, and is provided along the circumferential direction of the turbine. The circular shaped nozzle driving member provided around the turbine shaft in such a way that it is free to rotate by an actuator, drives the nozzle vanes. One end of a connecting member is fixed to the nozzle vane shaft of each nozzle vane, the other end of the connecting member is engaged with a recess or a hole through a connecting pin to engage with the nozzle driving member. The same number of connecting members are provided as the number of nozzle vanes. In the manufacturing method to manufacture such component part in the variable capacity turbine, the method is distinguished by comprising the steps of: forming either the nozzle driving member or the connecting member with a plate member, and forming the connecting pin as a single structure with the plate member by partially forcing a surface of the plate member to protrude in a column shape by pressing or by precision molding.
Furthermore, this invention is applied to the variable capacity turbine which is configured in the following way. The actuating gas is forced to flow from a spiral scroll formed in the turbine casing in a radial direction to the turbine rotor, through multiple nozzle vanes of which the angle is adjustable by the adjustable nozzle mechanism, for rotating the turbine rotor. The multiple nozzle vanes are provided on the nozzle mount fixed to the turbine casing in such a way that they are free to rotate, and are provided along the circumferential direction of the turbine. The circular shaped nozzle driving member provided around the turbine shaft in such a way that it is free to rotate by an actuator, drives the nozzle vanes. One end of a connecting member is fixed to the nozzle vane shaft of each nozzle vane, the other end of the connecting member is engaged with a recess or a hole through the connecting pin to engage with the nozzle driving member. The same number of connecting members are provided as the number of nozzle vanes. In the structure of a connecting member in the variable capacity turbine, it is distinguished by the configuration comprising: either the nozzle driving member or the connecting member formed with a plate member, and the connecting pin formed as a single structure with the plate member by partially forcing a surface of the plate member to protrude in a column shape.
According to the invention mentioned above, when it is manufactured the connecting pin which transmits the driving force to the counter member engaging with the recess or hole, etc. formed in the counter member of the component parts in the adjustable nozzle mechanism, and the plate member to engage with the connecting pin, it uses a manufacturing method to form a column shaped connecting pin protruding from a surface of the plate member as a single structure with the plate member, in other words, it uses either the pressing method comprising a step of pressing one side surface of the plate member towards the opposite side surface by a male molder to depress and form a depressed portion, and accepting the protrusion formed on the opposite side surface of the depressed portion into the molding cap of the female molder, or the precision molding method to form the connecting pin as a single structure with the plate member. Since the component part for the adjustable nozzle mechanism including the nozzle driving member and the connecting member connecting the nozzle driving member and the nozzle vanes are manufactured by these manufacturing methods, the work for forming the column shaped connecting pin on the component part by pressing or precision molding, specially the work for forming a plurality of connecting pins along a circumferential direction of the nozzle driving member, can be performed by a single process of pressing or precision molding.
This can eliminate the additional work necessary to manufacture the connecting pin separately from the nozzle driving member (link plate), as well as the work necessary to fix the connecting pins to the nozzle driving member. With this invention, since the nozzle driving member and the connecting pins, or the connecting member and the connecting pins are formed as a single structure, it can dramatically cut the manufacturing count and cost of the component part for the variable capacity turbine including the nozzle driving member and the connecting member as compared to the prior arts.
Further, by uniting the nozzle driving member and the connecting pins, or the connecting member and the pins, they can be a single structure, so the number of the component part will be decreased as compared to the prior arts in which the connecting pins are manufactured separately, and the total weight of the component part used in the variable capacity turbine will become lighter.